Oil well pump



B. F. SCHMIDT Jan. 5, 1965 OIL WELL. PUMP 2 Sheets-Sheet l Filed July 16, 1962 INVENTOR.

Jan. 5, 1965 B. F. SCHMIDT 3,164,102

oIL WELL PUMP Filed July 16, 1962 2 Sheets-Sheet 2 INVEN TOR.

United States Patent O 3,164,102 OIL WELL PUMP Benjamin F. Schmidt, 450 Fairview St., Sierra Madre, Calif. Filed July 16, 1962, Ser. No. 209,891 17 Claims. (Cl. MES-15S) This invention relates to and has for its primary object the provision of an improved oil well pump which will have an exceptionally long and ellcient working life by reason of the novel construction and arrangement of the parts thereof wherein no working part that is exposed to well fluid is operable in rubbing or frictional contact with any other part of the pump or well, thereby making it unnecessary frequently to replace or repair pumps, such as heretofore required in this art.

It is another object hereof to achieve the above objectives by providing an oil well pump in which tubular expansible and contractible elements such as bellows for effecting the pumping action, separate bodies of hydraulic operating fluid `and a novel fluid displacing unit operable for displacing the operating fluid to expand and contract the bellows, are carried by a closed and sealed tubular pump body in such a manner that this assembly when operatively positioned with upwardly opening check valves in the tubing of a well, will be operative to effect an efficient pumping operation without having the bellows come into frictional or rubbing contact with any part of the pump or the well and without exposing any interior part of the pump to well fluid.

It is another object of this invention to provide an improved oil well pump such as above described which in one form as here shown, will achieve the objects herein noted, in having upper and lower tubular bellows coupled to opposite ends of a tubular pump body with the bellows and the pump body sealed against entrance of well fluid in a novel manner and containing two bodies of hydraulic operating fluid separated by a piston in the pump body. A piston rod is connected with the piston and extends through and seals the upper end of the upper bellows with a portion of the rod above the bellows adapted to be operatively connected to suitable means above the pump for reciprocating the rod and piston. With this arrangement the upper end of the upper bellows will move with the piston rod and the piston will move so as to displace uid in the two fluid bodies in such a manner than on the down stroke the ripper vbellows will collapse and the lower bellows expand, with the reverse of this action taking place on the upstrolte, to thereby effect the pumping action with respect to well fluid exteriorly of the bellows, when the pump unit with a pair of upwardly open check valves are suitably positioned in the well tubing.

It is a further object of this invention to provide a pumpsuch as next above described which in one form may include in connected relation therewith a foot valve below the lower bellows adapted to seat in well tubing, and wherein an annular and upwardly opening check valve assembly .is carried 'by and surrounds the tubular pump body between the two bellows so as to form a seal with the pump body and a seat in the well tubing, thereby providing a complete pump unit including the valves and which may be positioned in well tubing ready for operation when the valves carried thereby are seated in the well tubing, and also providing for ready removal of the complete pump unit from the well when desired.

It is another object hereof to provide a pump of the character described which readily lends itself to being lowered in a well and removed therefrom as a complete unit on a wire line since it may be operated by a suitable motor operatively connected with the piston rod rather than by a conventional sticker rod, although a sucker rod could be used if desired.

sata2 ice Another object hereof is the provision of a pump such as described having a novel arrangement which prevents sanding up of the foot valve and related parts as well as detrimental exposure of other parts of the pump to sand and well fluid and at the same time controls in an eiiicient manner the ilow of well gas with respect to portions of the pump so that this gas will not interfere with the desired pumping operation.

Another object of this invention is the provision in an oil well pump of the character described of novel means for lling the two bellows and the pump body at the factory with the two bodies of hydraulic operating fluid which are displaced by the piston to elfect expansion and contraction of the bellows, this lling operation being made possible by use of a hollow por-tion of the piston rod communicating with the iluid chamber above the piston and in the upper bellows. The portion of this hollow rod above the upper bellows and the lower end of the lower bellows have filling openings, both o-f'which are normally closed by plugs removably fitted therein.

Another object of this invention is 4to provide in a pump of the character described novel means for guiding the bellows in the expansion and contraction thereof so as to avoid frictional engagement thereof with any part of the well o-r pump and to prevent buckling of the bellows, it being noted in this connection that the internal and external pressures to which the bellows are subjected in a well are substantially equal so that rupture or other failure thereof due to fluid pressure are prevented.

Other objects and advantages of the invention will be hereinafter described or will become apparent to those skilled in the art, and the novel features of the invention will be dened in the appended claims.

Referring to the drawings:

FIG. 1 is a fragmentary elevational view partly in section of a pump embodying the present invention as it would appear when positioned in a well;

FIG. 2 is a fragmentary vertical sectional view on an enlarged scale of the upper portion of the pump;

FIG. 3 is a fragmentary vertical sectional View on the Same scale as FIG. 2, of that lower section of the pump that is joined at its upper end to the lower end of the upper pump section shown in FIG. 2;

FIG. 4 is a vertical sectional view of the means for `securing the upper expansible and contractible pumping element of the pump to the reciprocable pump rod and for positively sealing the upper end of this pumping ele FIG. 5 is an enlarged sectional view taken on the line 5--5 of FIG. 2;

FIG. 6 is an enlarged sectional view taken on the line 6-6 of FIG. 3;

FIG. 7 is an elevational view of 'the valve unit shown in FIG. 6, with a surrounding portion of the unit shown in section;

FIG. 8 is an enlarged perspective View of a conical gas escape check valve;

FIG. 9 is an enlarged sectional view taken on the line 9 9 of FIG. 3; and v FIG. l0 is an enlarged sectional view taken on the lin lll-10 of FIG. 3.

Referring more specifically to the drawings, A designates an oil well pump embodying the present invention as it would appear when positioned in the tubing B of an oil well together with a foot valve C below the pump and an upwardly opening check valve assembly D located between the ends of the pump in surrounding and sealing engagement with the pump as well as in sealing contact with the tubing. The pump A is spaced circumferentially from the well tubing and thereby provides above and below the check valve assembly D, annular flow passages E and F for well fluid, the check valve D permitting liow of Well fluid from the lower passage F into the upper passage E in response to operation of the pump A in a manner which will be hereinafter described.

The pump A includes a sectional tubular pump body l extending above and belowthe upwardly opening check valvev assembly D which, as here shown, may be carried by the pump body l as a part ofthe pump and has sealing engagement with a seat 2 formed, as best shown in FIG. 3,'inter`nally of a joint section 3 of the well tubing B. Likewise, the foot valve C may be carried by a tubular extension tV of the pump body il for sealing Contact with an internal seat provided ina lower section d of the well tubing. With this arrangement the complete pump may bereadily positioned in the well tubing and as readily removed therefrom.

The tubular pump body l is open at opposite ends and is divided into upper and lower sections by a reciprocable piston 3 operable in a cylinder or barrel portion 9 of 4the pump body. v

Upper and lower tubular expansible and contractible pumping elements here shown as a bellows l@ and il and made of synthetic' rubber or other suitable material that is chemically inert to well fluid, are connected with opposite ends of the pump body l so as to form therewith a pair of sealed elongate chambers M and i5 separated by the piston 3. Each of these sealed chambers contains a body of hydraulic iluid which, in response to reciprocation pf the piston 8, will `cause the ibeliows lli and 11 to expand and contract longitudinally in the well tubing. As the bellows iti and ll constitute upper and lower end portions of the pump and are spaced circumferentially from the well tubing with their exterior surfaces exposed to well luid in the tubing, expansion and contraction of the bellows will effect, as will be hereinafter described, a pumping action effective 'to pump well lluid from the Well.

As a means for reciprocating the piston 8 to effect longitudinal expansion and contraction of the bellows it@ and 11, a piston rod 16 is connected with the piston and extends through the upper bellows lli, which latter at its upper end is connected with the piston rod so as to be movable therewith and so as to form a seal excluding entrance of welll fluid between the upper end of the bellows and the piston rod. 'The piston rod may .be connected to a motor operated drive unit, not shown, that may be lowered with the pump into the well, this unit being electrically, pneumatically or hydraulically operated and in eifect a part of the complete pump. lf desired, the piston rod i6 may be sucker rod operated, although a. motor operated drive unit connected 'with the pump to be lowered therewith in the well as above de- Y scribed may be preferred as a more eiiicient'operating means for the pum since it may be lowered and' raised with the pump on a wire line.V 1

Before describing the construction of the elements of the pump more specifically and the means whereby Vthe two bodies of operating uid sealed therein'and separatedv one from the other may be placed in the pump, it should be noted that the two bellows in being longitudinally expanded and contracted do not come in Contact with the well tubing and that the piston S' andy interior of the cylinder portion 9 of the pump body l as well as the entire interior of thepump do not Lcome in contact with the well uid and are therefore protected Nagainst wearY y and the abrasive action of sand'inthe well liuid the ends of the body, a iitting t7 screwed onto the upper end ot the cylinder portion 9 and having a central tubular guide member 13 through which ythe piston rod le is slidable. The tting i7 also provides for connection of the lower end of the upper bellows l@ to the upper end of the cylinder portion 9, the bellows being clamped so as to be sealed around the fitting by suitable clamping means 191 as shown in FIG, 2. The tubular guide le is held in the fitting by means of webs E@ and passages 2l formed between the webs to communicate the upper portion of the cylinder portion 9, in other words the charnber t4 above piston S, with the interior of the bellows iti.

The means for securing the upper end of the bellows 1t? with the piston rod t6 includes a partially split tubular itting 23 that is clamped on this rod by a clamping screw 2d threaded thereto to bind the split portion of the fitting to the rod as shown in FIG. 2. A sealing ring 2S in the fitting 23 seals against the rod le to prevent well uid from leaking between the rod and the tting. The lower end of the tting 23 is provided with a fiange 26 over which the upper end of the upper bellows l0 is fitted so as to be clamped around the litting sealed engagement therewith by suitable clamping means 27.

Means are provided to guide the upper bellows lil* to keep it from buckling and, as here shown, comprises a number of disks 28 axially spaced in the bellows and surrounding the piston rod i6 with their outer edges engaged with the inner surfaces of the surrounding wall of the bellows to hold this wall distended, there being openings Citi in the disks ZS to permit free iiow of the operating iiuid through the disks 2.8.

As shown in FiGS. l and 2, the upper end of the piston rod l5 may be threadedly coupled by upward extensions 3?; and 33 thereof to a sucker guide member 34 having flow grooves 35 thereon if the piston rod is to be sucker rod operated. if otherwise operated as by a motor driven means lowered into the well as hereinbefore mentioned, the piston rod lo may be connected in any suitable manner to such drive means.

lf desired, the piston rod 16 may be tubular to provide a chamber 3'? therein for containing some of the operating fluid confined in upper bellows l@ and in the upper chamber ld in the cylinder portion 9. This tubular form of the piston rod also facilitates the introduction into the upper chamber ld and upper bellows i@ of the proper amount of operating iuid that is conined above the piston S. The rod i6 is provided with ports 3S adjacent the upper side of the piston 3 for communicating the chamber 37 with upper chamber l@ in the cylinder portion 9, as shown in FIG. 2, and at its upper end the rod is closed by a removable plug di). Thus, on removing the plug iii the chamber le and the upper bellows l0 may be filled as required through the upper end of the rod t6. In this connection, it should be noted that the iitting 23 as shown in FIG. 4 is provided with an air vent passage 23 for Venting air from the bellows EL@ in iilling this bellows. After the filling operation a plug 23" is employed to seal this vent passage 23'.

The piston 3 as shown in FiG. 2, may be of any suitable form provided it will prevent flow of the operating fluid past it in the cylinder portion 9 of the pump. Fixed on the upper side of the piston in surrounding relation to the pump rod le is a fitting supporting a cushinning stop ring 42 adapted to abut the fitting 17 at the upper end of the cylinder portion Si to limit upward movement of the piston. The piston 8 is limited as to its downward movement by a stop member 43 secured to the lower side thereof by means of a threaded shank member te projecting from the stop member 43 and extending through the body l5 of the piston so as to be threaded into the lower end of the piston rod. This stop e3 and the threaded shank member ed secures the piston carried elements together and also connects the piston rod to the piston. in addition, the stop member 43 is disposed so as to contact a cushion ring t8 which,`

as shown at the top of FIG. 3, is positioned at the lower end of the cylinder portion 9 to limit downward movement of the piston with a cushioning action.

With reference to FIG. 3 which shows the construction of the lower section of the pump, it will be seen that the lower end of the cylinder portion 9 of the tubular pump body il has a threaded fitting 50 thereon in sealed engagement therewith and which has a threaded openingI 51 therethrough receiving the threaded upper end of the lowermost tubular section S2 of the tubular pump body 1. This tubular section 52 extends through the upwardly opening check valve D and at its lower end is flanged as at 53 and has the upper end of the lower bellows 11 clamped around the end 53 by means of suitable clamping means 54 which forms a fluid tight seal of the upper end of this bellows.

The lower end of the lower bellows 11 is closed by means of a plug 56 removably threaded into the bore of an annular closure member 57 within the bellows. This closure member has a threaded shank 5S projecting from the lower end of the bellows for reception of a nut 59 that is threaded on the shank so as to clamp the bellows between the nut and the inner flared end of the closure member 57 thereby sealing the lower end of the bellows. On removal of the plug 56 the bellows 11 and the lower chamber which includes lowermost tubular section 52 of the pump body 1 and the portion of the cylinder 9 below piston 8 may be filled as required with operating uid. This filling may be effected at the time the pump unit 1 is being prepared for use and complete/.i at the factory and may be easily carried out by inverting the pump assembly so that the bellows 11 is uppermost, the plug 56 after the lling being replaced to seal in the operating uid.

The check valve assembly D as shown in FIGS. 3 and 7, comprises an annular section 61 that surrounds the tubular section 52 of .the pump body i with the upper end of the upper section 61 thereof Aabutting the fitting 50 and sealed thereagainst by means of the sealing ring 62. The lower section 61 of the body 61 is supported by the seat 2 in the well tubing, there being a sealing ring 64 between the seat 2 and lower section 61 which latter has a bevelled lower end removably wedged in the seat 2. The lower section 61 is supported by a tubular member 55 surrounding the section 52 of the pump body 1 and resting on a shoulder 67 on section 52 and abutting the upper section 61. A ow passage 68 is provided through the sectional body 61 and terminates short of the upper end thereof in lateral port-s 69 in the upper section 61' and which will discharge well fluid into the upper annular passage E above the check valve assembly D during a pumping operation. Ports 79 formed in tubular portions '71 between the sections of the body 61 afford communication between passage 6% and the lateral ports 69, the ports 7u being normally closed by the ball valves 72 which seat on the upper ends of the tubular portions 71 and open the ports 7t in response to the pressure of well uid being pumped from the lower annular passage F in the well tubing.

As shown in FIGS. l and 3, the tubular extension 4 at the lower end of the pump body 1 and to which the foot valve C is attached, is connected with an annular enlargement 74 adjacent the lower end of the pump body section 52 to which the lower bellows 11 is connected. This tubular member 4 surrounds the bellows 11 which is circumferentially spaced therefrom and so maintained by one or more annular disks 75 surrounding the bellows,

there being openings 76 in the disks to permit free ilow of gas and well fluid therethrough, since the interior of the tubular member 4 denes a chamber 77 for containing well fluid that has entered from the foot valve through a port 78 in the valve and this fluid will be pumped out of the chamber 77 through ports 79 into the annular passage F inthe well tubing B in response to the pumping action of the lower bellows. In this connection, it should be noted that the foot valve C when unseated permits well huid to enter the annular passage F through lateral ports 80.

Gas that enters the chamber 77 will be relieved through vents 81 in the enlargement 74 at the lowerend of the lower tubular section 52 of the pump body 1, there being an annular conical closure 83 on the conical upper end of the enlargement 74 for normally closing the vents S1 and which opens only in response to pressure of gas seeking escape through the vents S1.

In the operation of the pump on the down stroke of the piston S the two bodies of hydraulic fluid on opposite sides of the piston are actuated and the upper end of the upper bellows 10 moves downward with the piston rod 16 and some of the upper body of operation fluid is withdrawn from Ithebellows 10 into the cylinder portion 9 with the descending piston thereby longitudinally collapsing and extending the upper bellows. At the same time some of the lower body of uid is forcedby the descending piston 8 into the lower bellows 11 and causes expansion thereof. This expansion of the lower bellows 11 causes well fluid surrounding it to be forced out of the chamber 77 through ports '79 and Si? into the lannular passage F, thence upwardly in the well tubing B through the check valve assembly D. In passing through the ports Si) the well fluid tends to wash sand and corrosives upwardly away from the foot valve.

On :the upstroke of the piston 8, some of the body of uid above the piston 8 is forced upwardly into the upper bellows 1t) causing it to expand and force upward in the well tubing, the well uid entrapped above the check valve -assembly D, such well fluid reaching the top of the well upon continued operation of the pump.

During the upstroke of the piston 8, it draws some of the lower body of operating tluid below the piston into the lower cylinder portion 9 of the pump from the lower bellows 11 which is thereby collapsed and creates a suction causing well iluid to rise above the foot valve C.

It should be noted that if the well in which the pump is installed is free of sand, the tubular member 4 attached to the lower end of the tubular pump body may be omitted and the lower bellows will then be operable in the lower part of the well tubing with a suitable foot valve, not shown, installed below the lower bellows in the tubing. The tubular member 4, as here provided, is most effective in sandy wel-ls, since when the bellows 11 therein is expanded, the well Huid in the member 4 is forced down by the bellows rather than upwardly, and with the velocity that sets up a turbulence and lifts from the foot valve C any sand that may have settled thereon, thereby forcing the sand away from the valve through the ports 79 and titl. Moreover, gas entrapped in the member 4 will escape through the vents 81 as the pressure of the gas lifts the closure 83, which latter is normally closed and prevents sand and well fluid from entering the vents 81.

It should be noted that the amount of operating fluid constituting the upper and lower bodies of fluid separated by the piston 8 is such that an adequate amount of such fluid will remain in the bellows to preventpcomplete collapse thereof when the piston 8 reaches the upper and lower limits of its stroke. In this connection, it should be noted that internal and external pressures on the bellows are substantially equal so that rupture and complete collapse of the bellows are prevented. The annular member surrounding the lower bellows 11 and the disks 28 within the upper bellows prevent lateral buckling of the bellows and, therefore, prevent damage thereof.

It will now be apparent that an oil well pump constructed tin accordance with the present invention is char-V acterized by the novel features as follows:

(l) Actuation of expansuble and contractible pumping elements by two separate bodies of operating hydraulic uid in closed circuits separated by a reciprocable piston aie-snee and cylinder unit which is sealed against exposure to well lluid and operates with less wear and friction than encountered with reciprocable well pumps as heretofore made. f g

(2) T he expansible and contractible elements are simultaneously operated one to expand and the other to contract on each stroke of the piston.

(3) The securing lof the upper end of the upper expansible and contractible pump element to a reciprocable piston rod for movement with the latter and for forming a seal excluding entrance of well fluid into the pump unit around the piston rod. y Y

The above noted and other advantages which are hereinbefore set orth establish that the pump hereol constitutes a noteworthy improvement in bellows type pumps as heretofore made.

While the pump unit of this invention as produced at the factory is operable as made inany well, it is to be understood that an operable pump assembly embodying this invention requires that the pump unit be positioned in well tubing with the two bellows exposed exteriorly to the well lluid as here shown and that suitable means be provided for reciprocating the piston rod and piston of the pump unit as hereinbefore described.

It is also to be understood that the foot valve C and upwardly opening check valve assembly D here shown as parts of the pump unitthat may be positioned in a well with the pump unit, could be of any suitable form other than here shown and carried by the well tubing, in which case the pump imit would seat thereon in a manner which iswell known in this art.

While specific structural details have been shown and described, it should be understood that changes and alterations may be resorted to without departing from the spirit of the invention as deiined in the appended claims.

I claim:

l. In a well pump: a tubular pump body; expansible and contractible bellows coupled to the ends of said pump body to constitute sealed expansible and contractible extensions of said pump body in fluid flow communication only with the interior of said pump body; a fluid displacement member in said pump body movable toward and away from said ends of said pump body; separate bodies of hydraulic operating fluid in said body and said bellows separated by said fluid displacement member and operable to expand and contract said bellows in response to said movements of said fluid displacement member; means for eiecting said movements of said Huid displacement member; means operatively associated with said pump body operable in response to said expansion and contraction of said bellows for directing well iluid upwardly around the exterior of said pump body in the well in which the pump is operated; and an upwardly opening check valve assembly surrounding said pump body above said last named means operable for retaining pumped fluid above it.

2H. in a well pump: a tubular pump body; expansible and contractible bellows coupled'to the ends ot said pump body to constitute sealed expansible and eontractible extensions of said pump body in iluid ilow communication only with the interior of said pump body; a lluid displacement member in said pump body movable toward' and away from said ends of said pump body; separate bodies ot hydraulic operating uid in said body and said bellows separated by said tluid displacement member and operable to expand and contract said bellows in response to said movements ot'said fluid'displacement member; rc-

Y ciprocable means extending through one of said bellows and the other of said check valve assemblies surrounding said pump body above the iirst mentioned checl; valve assembly for holding pumped fluid thereabove.

3. ln a well pump for operation in well tubing: a tubular pump body; expansible and contractible bellows coupled to the ends of said pump body to constitute sealed expansible and contractible extensions of said pump body in lluid flow communication only with the interior of said pump body; a fluid displacement member in said pump body movable toward and away from said ends of said pump body; separate bodies of lhydraulic operating fluid in said body and said bellows separated by said iluid displacement member and operable to expand and contract said bellows in response to said movements of said ilu-id displacement member; means for effecting said movements of said iluid displacement member; a foot valve depending rom the exterior of the lower end of said pump body; and an annular upwardly opening chccl; valve assembly surrounding and carried by said pump body between said bellows and adapted to seal against the Well tubing in which said pump body is disposed.

4. ln a well pump for operation in well tubing: a tubular pump body; hollow expansible and coutractible elements coupled to the ends of said pump body so that the interiors thereof are in communication with the interior of said pump body and the exterior only will be exposed to well fluid; a tluid displacement member in said pump body movable axially therein; separate bodies of bydraulic operating iluid conned in said body and said expansible and contractible elements and separated by said fluid displacement member and operable to expand and contract said expansible and contractible elements in response to axial movement oi said uid displacement member; means for effecting said movement of said fluid displacement member; a foot valve connected to and disposed below the louer end ot said pump body; and an upwardly opening check valve assembly surrounding and carried by said pump body between said expansible md contractible elements and adapted to seal against th well tubing.

5. in a pump assembly: a tubular pump body adapted to be positioned in well tubing; expansible and contractinle bellows coupled to the ends of said pump body to torni sealed extensions ot said pump body; a reciprocable pls-ton in said body; a body oi hydraulic lluid on each side oi said piston in said bellows; a reciprocable piston rod extending through one of said bellows in sealed engagement therewith and connected thereto so that said one bellows is rn therewith; said piston rod extendinto said body and being connected to said piston; and a pair ot valve assemblies exteriorly of said body and carried thereby adapted to seal against said well tubing; said pump and said bellows being circumlerentially spaced from said well tubing to provide an annular passage "or well fluid "etween said body and said 'well tubing for intaking well fluid through one of said valve assemblies and discharging Well iluid through the other of said valve assemblies in response to actuation of said bellows.

6. An oil 'well pump comprising: a tubular pump body; a tubular upper bellows coupled at one end to one end ot" said pump bod-y; means sealing the other end of said upper bellows; a tubular lower bellos-vs coupled at one end to the other end of said pump body; means sealing the other end of said lower oellows; said pump body and said two bellows constituting a sealed pump unit adapted to be positioned in tubing of a well in spaced relation thereto to denne therebetween a ilow pass-age for well fluid; means Vproviding below lower bellows a toot valve assembly for intaliing well fluid into said ow passage; means providing upwardly opening check valve assembly in said well tubing in surrounding relation to said pump Ibody between said upper and lower bellows and for torming a seal with said body and said well tubing; fluid displacing movable in said pump body between said bellows and forming therein two sealed chambers separated by said displacing means and with each chamber including one of said bellows; separate bodies of hydraulic uid sealed in said chambers and operable in response to movements of said displacing means to expand and contract said bellows; and operating means connected to said displacing means operable from the exterior of said pump body for moving said displacing means to displace said duid bodies and thereby expand and contract said bellows.

7. An oil well pump comprising: a tubular pump body; a tubular upper bellows coupled at one end to one end of said pump body; means sealing the other end of said upper bellows; a tubular lower bellows coupled at one end to the other end of said pump body; means sealing the other end of said lower bellows; said pump body and said two bellows constituting a sealed pump unit adapted to be positioned in tubing of a well in spaced relation thereto to define therebetween a ow passage for well fluid; means providing below said lower bellows a foot valve assembly for intaking well duid into said ilow passage; means providing an upwardly opening check Valve assembly in said well tubing in surrounding relation to said pump bodf,l between said upper and lower bellows and for forming aseal with said body and said well tubing; iluid displacing means movable in said pump body between said bellows and forming therein two sealed chambers separated by said displacing means and with each chamber including one of said bellows; separate bodies of hydraulic tluid sealed in said chambers and operable in response to movements of said displacing means to expand and contract said bellows; and means connected to said displacing means and extending outwardly through said upper bellows in sealed relation thereto for connection with means for effecting said movements of said displacing means.

8. An oil well pump comprising: a tubular pump body; a tubular upper bellows coupled at one end to one end of said pump body; means sealing the other end of said upper bellows; a tubular lower bellows coupled at one end to the other end of said pump body; means sealing the other end of said lower bellows; said pump body and said two bellows constituting a sealed pump unit adapted to be positioned in tubing of a well in spaced relation thereto to dene therebetween a rlow passage for well fluid; means providing below said lower bellows a foot valve assembly for intaking well lluid into said flow passage; means providing an upwardly opening check Valve assembly in said well tubing in surrounding relation to said pump body between said upper and lower bellows and for forming a seal with said body and said well tubing; fluid displacing means movable in said pump body between said bellows and forming therein two sealed chambers separated by said displacing means and with each chamber including one of said bellows; separate bodies of hydraulic fluid sealed in said chambers and operable in response to movements oi said displacing means to expand and contract said bellows; an operating member connected to said displacing means and movable for effecting said movements of said displacing means; said operating member being extended through said upper bellows for connection with means for effecting said movement thereof; and means connecting said upper bellows to said operating member for movement therewith,

9. An oil well pump comprising: a tubular pump body; a tubular upper bellows coupled at one end to one end of said pump body; means sealing the other end of said upper bellows; a tubular lower bellows coupled at one end to the other end of said pump body; means sealing the other end of said lower bellows; said pump body and said two bellows constituting a sealed pump unit adapted to be positioned in tubing of a well in spaced relation thereto to define therebetween a tlow passage for well fluid; means providing below said lower bellows a foot valve assembly for intaking well fluid Vinto said tlow passage; means providing an upwardly opening check Valve lassembly in said well tubing in surrounding relation to said pump body between said upper and lower bellows and for forming a seal with said body and said well tubing; a piston reciprocable in said pump body between the ends of said pump body dividing said body into two sealed 'chambers each of which includes one of said bellows; means providing p for the introduction into said chamber and bellows and the sealing therein of two bodies of hydraulic fluid separated by said piston and which fluid bodies, upon reciprocation of the piston, will cause expansion and contraction of said bellows; and a piston rod connected with said piston and extending through and above the upper end of said upper bellows in sealed engagement therewith to afford connection thereof with means for reciprocating said rod and said piston.

l0. An oil well pump comprising: a tubular pump body; a tubular upper bellows coupled at one end to one end of said pump body; means sealing the other end of said upper bellows; a tubular lower bellows coupled at one end to the other end of said pump body; means sealing the other end of said lower bellows; said pump body and said two bellows constituting a sealed pump unit adapted to be positioned in tubing of a well in spaced relation thereto to define therebetween a llow passage for well uid; a tubular member connected to the lower end of said pump body in surrounding and circumferentially spaced relation to said lower bellows and likewise spaced from said well tubing; a foot valve assembly carried by the lower end of said tubular member below said lower bellows; said foot valve assembly having ports for intaking well uid into said member as well as into said flow passage in the well tubing; said tubular member hav- -ing gas outlet port means; an upwardly opening closure normally closing said gas outlet port means; an annular upwardly opening check valve assembly surrounding said pump body between the ends of said pump body and operable to seal against the well tubing and the pump body; a piston reciprocable in said pump body between the ends of said pump body dividing said body into two sealed chambers each of which includes one of said bellows; means associated with said bellows providing for the introduction into said chamber and bellows and the sealing therein of two bodies of hydraulic uid separated by said piston and which upon reciprocation of the piston will cause expansion and contraction of said bellows; and a piston rod connected with said piston and extending through and above the upper end of said upper bellows in sealed engagement therewith to afford connection thereof with means for reciprocating said rod and said piston.

ll. An oil well pump comprising: a tubular pump body; a tubular upper bellows coupled at vone end to one end of said pump body; means sealing the other end of said upper bellows; a tubular lower bellows coupled at one end to the other end of said pump body; means sealing the other end of said lower bellows; said pump body and said two bellows constituting a sealed pump unit adapted to be positioned in tubing of a well in spaced relation thereto to define therebetween a flow passage for well fluid; means providing below said lower bellows a foot valve assembly for intaking welllluid into said ow passage; means providing an upwardly opening check valve assembly in said well tubing in surrounding relation to said pump body between said upper and lower bellows and for forming a seal with said body and said well tubing; fluid displacing means movable in said pump body between said bellows and forming therein two sealed chambers separated by said displacing means and with each chamber including one of said bellows; separate bodies of hydraulic fluid sealed in said chambers and operable in response to fluid displacement movements of said displacing means to expand and contract said bellows; and operating means connected to said displacing means operable from the exterior of said pump body for moving said displacing means to displace said fluid bodies and thereby expand and contract said bellows; said aie-sica ll i uid displacement means comprising a reciprocable piston and cylinder unit intermediate the ends of said pump body; said operating means for said displacement means comprising a piston rod.

12. An oil Well pump comprising: a tubular pump body; a tubular upper bellows coupled at one end to one end of said pump body; means sealing the other end of said upper bellows; a tubular lower bellows coupled at one end to the other end of said pump body; means sealing the other end of said lower bellows; said pump body and said two bellows constituting a sealed pump unit adapted to be positioned in tubing of a well in spaced relation thereto to define therebetween a iiow passage for well liuid; means providing below said lower bellows a foot valve assembly for intaking well huid into said flow passage; means providing an upwardly opening check valve assembly in said well tubing in surrounding relation to said pump body between said upper and lower bellows and for forming .a seal with said body and said Well tubing; fluid displacing means movable in said pump body between said .bellows and forming therein Vtwo sealed chambers separated by said displacing means and with each chamber including one of said bellows; separate bodies of hydraulic uid sealed in said chambers and operable in response to fluid displacement movements `of said displacing means to expand and contract said bellows; operating means connected to said displacing means operable from the exterior of said pump body for moving said displacing means to displace said fluid bodies and thereby expand and contract said bellows; said fluid displacement means comprising a reciprocable piston and cylinder unit intermediate the ends of said pump body; said operating means for said displacement means comprising a piston rod; said piston rod having a tubular portion extending into and from said upper bellows and having a iilling opening in the portion above said upper bellows; Va plug removably iitted in said llling opening; and the means for sealing said lower bellows including a illing opening and a plug removably tted in said last named iilling opening.

13. n a well pump; a tubular pump body; expansible and conuactible bellows coupled to said pump body in iiuid flow communication with the interior of said pump body; a duid displacement member movable in said pump body for displacing fluid therein; separate bodies of hydraulic operating fluid coniined in said pump body and said bellows and separated by and displaceabie upon movements of said iiuid displacement member so as to expand and contract` said bellows; means forieftecting said v movements of said uid dispiacement member; and upwardly opening check valve assemblies operatively associated with said pump body; one of said check valve assemblies being located to permit well fluid to rise thereabove exteriorly of said pump body upon actuation of said bellows; the other of said check valve assemblies surrounding the exterior of said pump body above one valve assembly.

14. In a well pump: a tubular pump body; expansible and contractible bellows coupled to said pump body in fluid ow communication with the interior of said pump body; a iluid displacement member movable in said pump body for displacing huid therein; separate bodies or hydraulic operating Huid confined in said pump body and said bellows and separated by and displaceable upon movements of said fluid displacement member so as to expand and contract said bellows; an upwardly opening check valve assembly carried by said pump body between said bellows and adapted to form a seal with well tubing in which lthe pump is positioned; and a foot valve assembly connected to said pump body and disposed belowthe lower end thereof.

l5. In a well pump: a tubular pump body; a piston reciprocable in said pump body; a piston rod connected to said piston; a plurality of expansible and contractible elements coupled to said pump body in fluid How communication with the interior of said pump body; means connecting one of said expansible and contractible elements with said piston rod for movement therewith; operating oil in said pump body and said expansible and contractible elements; said oil being disposed on opposite sides of said piston; means on said piston rod for connection with means for `reciprocating said rod and said piston; an upwardly opening annular check valve assembly surrounding said pump body for conning thereabove exteriorly of said pump body well fluid pumped thereabove; and a second upwardly opening check valve operatively associated with said pump body operable in response to expansion and contraction of the lowermost of said expansible and contractible elements for admitting well iiuid to pass through said annular check valve assembly.

i6. In a well pump: a tubular pump body; a piston reciprocable in said pump body; a piston rod connected to said piston; a plurality of expansible and contractible elements coupled to said pump body in duid flow communication with the interior of said pump body; means connecting one of said expansible and contractible elements with said piston rod for movement therewith; operating oil in said pump body and said expansible and contractible elements; said oil being disposed on opposite sides of said piston; means on said piston rod for connection with means or reciprocating said rod and said piston; an upwardly opening check valve assembly carried by said pump body between said expansible and contractible elements; means embodied in said check Valve assembly for forming a seal with said pump body and well tubing in which the pump is positioned; and an intake valve assembly connected to said pump body and disposed below said check valve assembly.

i7. ln a well pump: a tubular pump body; a piston reciprocable in said pump body; a piston rod connected to said piston; a plurality of expansible and contractible elements coupled to said pump body in iiuid ow communication with the interior of said pump body; means connecting one of said expansible and contractible elements with said piston rod for movement therewith; operating oil in said pump body and said expansible and contractible elements; said oil being disposed on opposite sides of said piston; means on said piston rod for connection with means for reciprocating said rod and said piston; a tubular member surrounding and circumferentialiy spaced from said pump body defining therebetween an annular flow passage for well iuid; a check valve assembly carried by said pump body between said expansible and contractible elements; a seat for said check valve assembly located in said tubular member; said tubular member having an intake valve seat below said pump body; and an intake valve assembly on said intake valve seat.

Reerences Cited by the Examiner UNlTED STATES PATENTS 1,662,029 3/28 Harrington 103-165 1,675,434 7/28 Amburgh l03*165 2.191,81@ ffl/ff() Rymal 10121-148 2,277,306 3/42 Coiey 103-44 2,814,993 12/57 Schmidt 10S-46 FOREIGN PATENTS 613,189 5/35 Germany. 1l6,ll7 5/18 Great Britain.

LAURENCE V. EFNER, Primary Examiner. 

6. AN OIL WELL PUMP COMPRISING: A TUBULAR PUMP BODY; A TUBULAR UPPER BELLOWS COUPLED AT ONE END TO ONE END OF SAID PUMP BODY; MEANS SEALING THE OTHER END OF SAID UPPER BELLOWS; A TUBULAR LOWER BELLOWS COUPLED AT ONE END TO THE OTHER END OF SAID PUMP BODY; MEANS SEALING THE OTHER END OF SAID LOWER BELLOWS; SAID PUMP BODY AND SAID TWO BELLOWS CONSTITUTING A SEALED PUMP UNIT ADAPTED TO BE POSITIONED IN TUBING OF A WELL IN SPACED RELATION THERETO TO DEFINE THEREBETWEEN A FLOW PASSAGE FOR WELL FLUID; MEANS PROVIDING BELOW SAID LOWER BELLOWS A FOOT VALVE ASSEMBLY FOR INTAKING WELL FLUID INTO SAID FLOW PASSAGE; MEANS PROVIDING AN UPWARDLY OPENING CHECK VALVE ASSEMBLY IN SAID WELL TUBING IN SURROUNDING RELATION TO SAID PUMP BODY BETWEEN SAID UPPER AND LOWER BELLOWS AND FOR FORMING A SEAL WITH SAID BODY AND SAID WELL TUBING; FLUID DISPLACING MEANS MOVABLE IN SAID PUMP BODY BETWEEN SAID BELLOWS AND FORMING THEREIN TWO SEALED CHAMBERS SEPARATED BY SAID DISPLACING MEANS AND WITH EACH CHAMBER INCLUDING ONE OF SAID BELLOWS; SEPARATE BODIES OF HYDRAULIC FLUID SEALED IN SAID CHAMBERS AND OPERABLE IN RESPONSE TO MOVEMENTS OF SAID DISPLACING MEANS TO EXPAND AND CONTRACT SAID BELLOWS; AND OPERATING MEANS CONNECTED TO SAID DISPLACING MEANS OPERABLE FROM THE EXTERIOR OF SAID PUMP BODY FOR MOVING SAID DISPLACING MEANS TO DISPLACE SAID FLUID BODIES AND THEREBY EXPAND AND CONTRACT SAID BELLOWS. 